U.S. patent number 3,589,632 [Application Number 04/820,468] was granted by the patent office on 1971-06-29 for self-forming-boom storing and deploying apparatus.
This patent grant is currently assigned to Westinghouse Electric Corporation. Invention is credited to James A. Rew.
United States Patent |
3,589,632 |
Rew |
June 29, 1971 |
SELF-FORMING-BOOM STORING AND DEPLOYING APPARATUS
Abstract
Improved apparatus which stores and deploys rolled-up thin,
springlike, strip material that self-unwinds and curls outwardly at
its edges into a hollow tubular boom when freed of its wound state.
Self-adjusting means radially constraining the edges of the
outermost winding of the rolled-up strip maintains same compactly
wound on the storage reel during self-unwinding, and one-way
ball-type centrifugal brake means on the reel stabilizes the
strip-unwinding rate while permitting unrestrained reel rotation in
the winding direction.
Inventors: |
Rew; James A. (Reistertown,
MD) |
Assignee: |
Westinghouse Electric
Corporation (Pittsburgh, PA)
|
Family
ID: |
25230851 |
Appl.
No.: |
04/820,468 |
Filed: |
April 30, 1969 |
Current U.S.
Class: |
436/509;
242/390.3; 242/396.6; 242/580.1; 242/614; 436/533; 436/805;
188/82.84; 436/534; 242/390.8 |
Current CPC
Class: |
F16H
19/064 (20130101); B21C 47/003 (20130101); B65H
75/34 (20130101); B21C 47/18 (20130101); H01Q
1/1235 (20130101); E04C 3/005 (20130101); B21C
47/28 (20130101); Y10S 436/805 (20130101); B65H
2701/332 (20130101) |
Current International
Class: |
B65H
75/34 (20060101); B21C 47/28 (20060101); B21C
47/18 (20060101); B21C 47/00 (20060101); H01Q
1/12 (20060101); B65h 075/00 () |
Field of
Search: |
;242/54,54A,55,84.8,99,107,107.3,156.1 ;52/108 ;188/82.84 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Gilreath; Stanley N.
Assistant Examiner: Schroeder; Werner H.
Claims
I claim:
1. Extensible boom apparatus, comprising,
a support frame,
a storage reel having a central hub rotatably mounted in said
support frame,
strip guide means mounted on said frame a distance away from said
reel,
an elongated spring strip of thin springlike material attached at
one end to said hub and wound compactly therearound in a widthwise
flattened state and having its opposite end extending tangentially
from its reel-wound turns through said guide means,
said strip being inherently biased to unwind and project itself
through said guide means while curling itself outwardly at its
edges to form itself into a hollow cylindrical configuration,
self-adjusting coil keeper means on said storage reel at opposite
ends of said hub exerting a resilient radially inward constraint at
the edges of the outermost turn of the spring strip to maintain
such strip compactly wound on the reel hub during payout unwinding
of the strip from the reel and consequent reduction in diameter of
such outer turn, and
a centrifugal friction brake means interposed between said frame
and reel to limit the rate at which strip payment is permitted by
freedom of reel rotation.
2. Extensible boom apparatus, comprising,
a support frame,
a storage reel having a central hub rotatably mounted in said
support frame,
strip guide means mounted on said frame a distance away from said
reel,
an elongated spring strip of thin springlike material attached at
one end to said hub and wound compactly therearound in a widthwise
flattened state and having its opposite end extending tangentially
from its reel-wound turns through said guide means,
said strip being inherently biased to unwind and project itself
through said guide means while curling itself outwardly at its
edges to form itself into a hollow cylindrical configuration,
and self-adjusting coil keeper means on said storage reel at
opposite ends of said hub exerting a resilient radially inward
constraint at the edges of the outermost turn on the spring strip
to maintain such strip compactly wound on the reel hub during
payout unwinding of the strip from the reel and consequent
reduction in diameter of such outer turn, said turns keeper means
comprising rigid inwardly facing conical members at opposite ends
of the hub, and
helical compression spring means biasing the two conical members
toward one another.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
Deployable boom apparatus in which a thin elongated strip wound in
a widthwise flattened state is self-biased to unwind and curl
edgewise into an extended hollow cylindrical configuration.
2. Description of the Prior Art
In deployable boom apparatuses which store springlike metal strip
in wound widthwise flattened form on a storage reel and are
operable to permit self-biased unwinding extension with edgewise
curling of such strip into an extensive hollow cylindrical
configuration, it has been the practice, as in U.S. Pat. No.
3,144,104 to Weir et al., FIGS. 2 and 3, to so wind the strip onto
the reel that its curl-prone edges face radially outward, and to
retain the wound turns on the reel by conical keeper discs at
opposite ends of the reel that slant inwardly in radially
restraining circumferential contact with the edges of the outermost
turn of the wound strip. When the reel is freed for turning about
its central axis, the tape unwinds from the reel as the outermost
turn curls itself edgewise and self-extends into hollow tubular
form. Although in Weir et al., the axial separation distance
between the conical keeper disc at opposite ends of the reel is
adjustable to suit different numbers of initial strip windings,
such distance remains fixed after having been adjusted to suit a
fully loaded reel with a given number of turns, or windings, so
that during subsequent deployment of the boom as the outermost turn
of the strip maintains contact with the rotating conical keeper
disc on the reel and continuously exits tangentially therefrom, the
inner turns progressively expand in diameter, bloom out, and
continuously redistribute themselves in the annular space between
the central hub of the reel and the keeper discs. This results in a
sliding movement between the turns of the strip as same unwinds
from the reel and thus departs from a pure unwinding action. At
least in the cases where the spring strip edges are notched to
provide an interlocking boom seam, as in FIG. 8 of the Weir et al.
patent, for example, such relative sliding movement between the
spring strip turns during deployment from the reel can interfere
with self-unwinding deployment of such strip, so that resort is
made to powered arrangements such as in FIG. 7 of Weir et al.
patent, where the strip is maintained tensioned on the reel between
power-driven pinch rolls that pay out the strip from the reel and a
slipping belt and pulley arrangement that sprags rotation on the
reel.
SUMMARY
The present invention, in providing a strip storage reel having
self-adjusting keeper means which operates to maintain the spring
strip turns compactly wound around the reel during deployment,
hence results in pure nonslip unwinding of the strip, readily
enables the strip to be self-unwound without need for pinch-roll
payout, even in the case of notched-edge interlock-seam boom
strips. Furthermore, such self-adjusting keeper means affords
opportunity for payout control through the medium of a motor on the
hub portion of the reel, which may also serve for strip windup.
Payout rate control is provided by a centrifugal ball-type
friction-braking means on the reel.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view, in outline, of an improved
self-forming and self-deploying extensible boom apparatus embodying
the present invention;
FIGS. 2 and 3 are end and side elevation views, respectively,
showing in outline one exemplification of a novel strip storage
reel of the present invention as employing self-adjusting keeper
means for the strip windings;
FIG. 4 is a cross-sectional view in side elevation, showing an
alternate construction of a self-adjusting winding keeper reel
constructed in accord with features of the present invention;
FIGS. 5 and 6 are plan views, in outline, showing the action of a
compound form of self-adjusting strip keeper means of the type
shown in FIGS. 2 and 3;
FIG. 7 is an end elevation view, partly in outline and partly in
section, of a ball-type centrifugal friction break means for
regulating the rotary speed of the strip storage reel during
self-energized unwinding deployment of the strip stored on the
reel; and
FIG. 8 is a section view taken along the line VIII-VIII in FIG.
7.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, the improved self-forming, self-extending boom
apparatus comprises a rigid frame means 10 in which is rotatably
mounted a storage reel 11 having a hub portion 12 journaled in the
frame for turning about an axis 13 and to which the innermost end
of the boom-forming spring strip 14 and around which such strip is
wound for storage in a manner in which its self-curling edges face
outwardly of the hub and become flattened widthwise of the strip as
wound therearound. The strip 14, in accord with prior practice for
use as extensible spaced booms, for example, is composed of metal,
such as beryllium copper, properly heattreated to have a springlike
characteristic that, when wound in coil form around the reel hub
12, is self-biased toward straightening out and curling edgewise
into a hollow tubular boom 15 as for projection in space aboard a
satellite to obtain gravity gradient stabilization, for example.
Opposite side edges of the strip 14 may be notched to form a series
of tabs 16 that interlock together during deployment to form a lock
seam 17 for the boom 15 formed by such strip. An assemblage of
guide rollers 18 and 19, rotatably mounted on the frame 10,
cooperate with the inner and outer surfaces of the strip 14,
respectively, to direct such strip tangentially from the reel 11 as
its edges begin to curl together upon becoming free from such reel
en route to assuming the hollow tubular configuration of the boom
17 it self-forms into.
Referring to FIGS. 1, 2, and 3, in accord with a prime feature of
the present invention, a self-adjusting keeper means is provided on
the reel 11 to maintain the strip windings thereon in a compactly
wound state during storage thereon as well as during unwinding of
the strip in self-ejecting extension into projecting boom shape. In
the illustrative form shown in these figures, the self-adjusting
keeper means takes the form of a plurality of spring tabs or
fingers 18 of thin elongated form which are secured at an inner
radial end to the hub 12 of the reel and which extend radially
outward and axially inward of such hub at a number of
circumferentially spaced-apart locations at both hub ends. The
fingers 18 are made of such as spring steel and shaped to act as
flexure springs which exert a radially inward force at the edges of
the outermost turn of the spring strip 14 wound on the reel 11. The
keeper fingers 18 are so constructed and arranged as to maintain
such retaining force against the outer turn edges of the strip 14
during unwinding of the strip from the fully loaded to the fully
unloaded states of the reel, as such outer turn unwinds from the
reel and becomes progressively closer to the hub 12. Also, the
spring fingers 18 are so proportioned relative to the separation
distance between the partially curled edges of the strip 14 as it
leaves the reel 11 tangentially therefrom, that the maximal inward
projection of the ends of such fingers, which occurs when the last
several turns of the strip 14 remain on the hub 12 in compactly
wound state thereon, will not engage such tangential strip region
as the fingers rotate with turning of the reel hub during the strip
unwinding. Flat, slotted discs 20 attached to opposite ends of the
hub 12 of the storage reel 11, provide for locating the fingers 18
as well as protecting same during handling of the reel, as during
assembly of the apparatus.
In FIGS. 5 and 6 is illustrated an extension of the spring finger
18 concept of FIGS. 1 to 3, wherein several circumferential arrays
of such fingers are employed at different radial distances away
from the hub 12 of the storage reel 11 for the strip 14, to enable
accommodation of a greater number of strip turns on the reel
without causing interference between the rotating fingers 18 and
the edge-curling tangential region of the strip leaving the reel
during unwinding deployment. FIG. 5 shows the keeper action of the
outermost fingers 18 on a fully loaded reel while the inner fingers
18 are held in retracted readiness by the ends of the strip
windings. FIG. 6 shows keeper action of the inner fingers 18 when
only several turns of the strip 14 remain on the hub 12, while also
showing that the fully projecting idle outer fingers 18 will clear
the curling side edges of the tangentially leaving strip 14.
Referring to FIG. 4, the reel 11 of the present invention,
embodying self-adjusting keeper means for maintaining the outermost
turn of the wound strip 14 clamped at its edges constantly during
unwinding of such strip, may take the alternate form as shown,
which substitutes, for the fingers 18, a pair of inwardly facing
conical rims 22 attached to opposite ends of a telescoping hub 23
biased by a helical compression spring 24 which constantly urges
the two rims 22 toward one another to maintain such outer turn
contact with the strip.
For windup of the strip 14 onto the reel 11, such as an electric
motor 27 of FIG. 1, may be employed. Locking means, not shown, is
provided for securing the reel hub 12 against rotation, thereby
preventing unwinding of the strip until the desired time, when the
reel hub 12 will be unlocked to permit its rotation by action of
the self-energized unwinding strip 14.
Referring to FIGS. 1, 7, and 8, during self-energized unwinding
projection of the spring strip 14 from the reel 11, it becomes
important to limit the rate of payout of the tangentially leaving
strip. In the present apparatus this is done by a centrifugal
ball-type friction brake that imposes a degree of rotary restraint
on the hub 12 of the reel according to rate of turning of such hub,
thereby to obtain a limited turning rate for such hub during strip
payout. A rotary part 30 of the brake means is secured to rotate
with the hub 12 of the strip storage reel 11, as by attachment to a
common shaft 32 journaled in the frame means 10. Rotary part 30
includes a number of circumferentially spaced-apart sockets or
cavities 34 which open outwardly from a circular outer peripheral
portion of such part and in which are disposed a number of ball
members 36, one in each cavity. Encircling the rotary part 30,
there is a stator ring 38 which is secured against rotation to a
portion of the frame 10. Stator ring 38 has an annular tapered
friction surface 40 that extends radially and axially inward. In
the relaxed state of the brake, when the reel hub 12 is not
turning, the balls 36 rest only lightly against the surface 40 if
at all. During rotation of the part 30, the balls 36 are caused by
centrifugal force to travel outwardly of their cavities 34 into
rolling and slipping engagement with the tapered annular friction
surface 40 of the stator ring 38 and become wedged between such
surface 40 and a radial wall 42 in each cavity 34 to impose a
restraint to relative rotation between the two parts 30 and 38,
thereby between the frame means 10 and the reel hub 12, which
varies in degree according to rate of rotation of such hub. This
form of centrifugal braking means tends to maintain its
effectiveness even in the presence of wear of the friction parts,
since the balls 36 will merely assume deeper positions along the
tapered annular friction surface as any wear progresses. In the
exemplified configuration of FIGS. 1, 7, and 8, such brake means is
rendered ineffective during strip windup, by provision of radially
extending sloping end walls 44 for the cavities 34 in rotary part
30, which causes the balls 36 to move radially inward away from the
tapered annular friction surface on the stator ring 38.
* * * * *